Pleated jet skirting for ground effect machines



July 12, 1966 J. HENRY 3,260,323

PLEATED JET SKIRTING FOR GROUND EFFECT MACHINES Filed July 29, 1963 5Sheets-Sheet l INVENT OR JOHN HENRY BY 0 5mg y ATTORNEYS July 12, 1966J. HENRY 3,2 23

PLEATED JET SKIRTING FOR GROUND EFFECT MACHINES Filed July 29, 1963 5Sheets-Sheet 2 INVENTOR JOHN HENRY ATTOR NE'YS July 12, 1966 J. HENRY3,2

PLEATED JET SKIRTING FOR GROUND EFFECT MACHINES Filed July 29, 1965 5Sheets-Sheet :3

INVENTOR JOHN HENRY BY o rwl g ATTORNEYS United States Patent 3,260,323PLEATED JET SKIRTING FOR GROUND EFFECT MACHINES Ilohn Henry, Cowes, Isleof Wight, England, assignor to Westland Aircraft Limited, Somerset,England Filed July 29, 1963, Ser. No. 298,382 9 Claims. (Cl. 180-7) Thisinvention relates to ground eflect machines and is concerned with theconstruction of flexible jet base skirtings such as are proposed, forexample, in British Patents 860,781, 925,425 and 929,671.

During the operation of such machines, and more particularly duringoverwater operations, I have found that flexible jet skirting, at and inthe vicinity of the stern, is subjected to greater stresses than mightbe expected, due to forward movement of the machine. This occurs sincethe forward curvature of the skirting from the astern position toencompass the sides tends to dig in or scoop water instead of partingthe water or flexing inwardly as at the bow or sides. Such extrastresses however, also occur on skirting positioned at what may betermed the trailing side of the bow, side or stern quarter when theforward movement of the machine has a crabwise attitude relative to thesurface over which it is operating, as in running cross-seas orcrosswinds, or when a banked turn is made and the trailing edge dipsinto the water.

Considering a skirting arranged to retard escape of the ground effectpressurised gaseous cushion, these extra stresses are applied outwardfrom the cushion area. They are exerted to act upon the skirting in adirection against which flexing of the skirting is normally restrainedto re sist the cushion pressure. The applied extra stresses are bigenough to cause splitting of the skirting on many occasions.

The object in this invention is to provide a new or improvedconstruction of flexible jet skirting for side, end

or peripheral applications, which can flex outwardly under stresses ofthe kind described, whilst remaining operative to retard escape of thegaseous ground-eflect cushion, and also being capable of otherwiseflexing when struck by obstacles.

Accordingly this invention consists in a ground effect vehicle providedwith a fluted, or pleated, fieXible jet skirting system, attached tosuspend from the base structure of the machine in a normal fluted orpleated state and in which a degree of inherent rigidity resists outwardflexing under the influence of the ground effect cushion pressure, and'biasses the skirting to re-assume the fluted, or pleated state afterflexing in any direction, the arrange ment being such that in additionto being able to flex when obstacles are struck, the skirting can flareoutwardly from the bottom by flexing to unfold the flutes, or pleats,and relieve excessive pressures whilst maintaining retarding action tothe escape of the gaseous ground effect cushion.

Further objects and advantages of the invention will become apparentfrom the following detailed description with reference to theaccompanying drawings, which are by way of example only, wherein:

FIGURE 1 is an elevation in section through the base platform, ductingand flexible skirting according to the invention.

FIGURE 2 is a diagram of the flexible skirting according to theinvention, sectioned along line IIII of FIG- URE 1.

FIGURE 3 is a diagram of the flexible skirting according to theinvention, sectioned along line IIIIII of FIGURE 1.

FIGURE 4 is a perspective view of the flexible skirting according to theinvention and as shown in FIGURES 1, 2 and 3.

FIGURE 5 is a diagram similar to FIGURE 3, showing the flutes or pleatsextended, according to the invention.

FIGURE 6 is a diagram similar to FIGURE 3, but showing an alternativemethod of construction of the flexible skirting according to theinvention.

FIGURE 7 is a diagram similar to FIGURES 3 and 6 but showing a furtheralternative method of construction of the flexible skirting according tothe invention.

In carrying the invention into effect according to one convenient form,by way of example only with reference to FIGURES 1-5, the rigid baseplatform 1 of a peripheral jet type ground effect machine carries arigid air or gas supply duct 2 around the periphery. The duct 2 conveysair drawn from atmosphere to peripheral pressure jet orifices 3, throughwhich air is discharged downwardly.

The air is pressurised within the duct 2 by one or more centrifugalfans, not shown. The pressure air discharge from the jet orifices 3generates the ground effect pressurised air cushion between the surface4, over which the machine is operating, and the base platform 1.

The duct 2 is flexibly extended a predetermined distance beneath theplatform 1 by a flexible skirting assembly generally indicated at 5, theflexible skirting assembly 5 being attached to the rigid walls 6 by anysuitable method. It is made of rubber, plastic, rubberised orplasticised fabric, or any other flaccid or flexible hard wearingmaterial made up to resist abrasion. The distance the flexible skirtingassembly 5 extends the duct 2 below the platform 1 is predetermined inaccordance with the operational role of the vehicle.

The flexible skirting assembly 5 comprises pleats, or flutes, preferablyincorporated in the form of flexible folded webs 7 of U or V shape, thelegs of the U or V connecting adjacent air or gas flexible ducts 8arranged in side-by-side relationship in the form of tubular members,the fold in the webs 7 occurring centrally thereof in a substantiallyvertical plane and the ends of the legs being attached to the flexibleducts by any suitable means, such as stitching or staples. In thepreferred embodiment illustrated, the air or gas flexible ducts 8 arefunnel-shaped with the larger orifice 9 at the top for connection to therigid air or gas supply duct 2 of the machine, and tapering towards thebottom to form the jet orifice 3, and may be constructed by attachingtwo portions together, the two portions being an inner wall 10 and anouter wall 11.

The attachment of the inner wall 10 to the outer wall 11 may be achievedconveniently, by using the same stitching and staples that attach thewebs 7 to the flexible ducts 8 and could thus be performed in oneoperation. The jet orifice 3 may be inwardly inclined to impart aninward component to the jet discharge, so that each flexible duct 8 israther like 21 Wellington boot with an open toe forming jet orifice 3.Such an arrangement utilises the inflationary pressure of the air or gasto provide an element of inherent rigidity maintaining and biassing theflexible skirting assembly 5 to assume or remain in thedownwardly-extended position.

The pleats or flutes may alternatively be incorporated in the formillustrated in the FIGURES 6 and 7, wherein two legs 12 are attached toeach other, by stitching, staples or any other suitable means ofattachment, in a substantially vertical plane, the other ends of thelegs 12 being attached to adjacent air or gas flexible ducts 8 in themanner already described. FIGURE 7 shows an alternative form ofconstructing the flexible ducts 8, wherein the outer wall comprises twoportions 13 attached to each other, by stitching, staples or any othersuitable means of attachment, in a substantially vertical plane.

The assembly of webs and ducts can be constructed to form a continuousflexible peripheral base skirting, side wall, end wall, bow or stemskirtings, or could be incor porated as part of a continuous skirtingwhich varies in construction and configuration according to the part ofthe machine at which it is located. Where advantageous, the inventioncould be used for stability jet skirting or keels or cushioncompartmentation divisions which extend flexibly from the basestructure.

In the preferred construction, the webs 7 are attached to the air or gasducts 8 in such a manner so that, when the flexible skirting assembly 5flares out to unfold the pleats, or flutes, the webs 7 are located atthe inner edge of the air or gas ducts 8, which consequently stand roudas ribs on the outside of the flexible skirting assembly 5, relativelyto the machine. In this way the stretched webs 7, with the inner wallsof the air or gas ducts 8, present a substantially smooth continuousskirt surface on the cushion side, against which any excessivepressures, as described, are exerted. To this end, it will be understoodthat the webs 7 normally lie as folded pleats or flutes between adjacentpairs of air or gas ducts 8.

This invention constitutes a development of the construction describedin British Patent 929,671. It will be apparent to anyone skilled in theart that the flexible skirting assembly 5, comprising the webs 7 and theair or gas flexible ducts 8, may alternatively be moulded in one piece,such that the entire peripheral skirting assembly 5, may be constructedof one integral moulding or alternatively of an assembly of severalsections, each section consisting of an integral moulding of severalwebs 7 and flexible ducts 8.

I claim as my invention:

1. A ground effect vehicle provided with a fluted or pleated flexiblejet skirting system through which air under pressure is dischargeddownwardly to build up and maintain the air pressure of the groundeffect air cushion, the system forming also a flexible barrier to thedissipation of pressurised air constituting the ground effect aircushion associated with the barrier, and comprising an assembly offlexible tubular components formed of a flaccid impervious material soas to be flexible in all lateral directions and arranged in side by siderelationship to depend downwardly from the base of the vehicle, saidtubular components being open at both ends for passing pressurized airdownwardly therethrough, adjacent pairs of flexible tubular componentsbeing connected by flexible folded webs, said flexible tubularcomponents being funnel shaped with the larger orifice at the top andtapering toward the bottom to form a jet orifice, the jet orifice beinginwardly inclined to impart an inward component to the jet discharge,the inflationary pressure of the air or gas flowing through saidflexible tubular components providing an element of inherent rigiditymaintaining and biasing said flexible jet skirting system to assume orremain in the downwardly extended position.

2. A ground effect vehicle provided with a fluted, or pleated, flexiblejet skirting system as claimed in claim 1, wherein said flexible foldedwebs are of U or V shape, the legs of said U or V shaped flexible websbeing attached to adjacent flexible tubular components.

3. A ground effect vehicle provided with a fluted or pleated flexiblejet skirting system, as claimed in claim 2, wherein the fold in saidflexible folded webs occurs substantially centrally thereof and has avertical disposition.

4. A ground effect vehicle provided with a fluted or pleated flexiblejet skirting system, as claimed in claim 1, wherein said flexibletubular components are formed by two portions, said two portionscomprising an inner wall and an outer wall.

5. A ground effect vehicle provided with a fluted or pleated flexiblejet skirting system as claimed in claim 4 wherein said inner wall, saidouter wall and said flexible folded webs are mutually attached bystitching.

6. In a ground effect machine having an elongated duct opening to whichpressurized fluid is passed, a flexible jet skirting system comprising:a plurality of hollow tubular members formed of a flaccid imperviousmaterial so as to be flexible in all lateral directions and disposed inside-by-side relationship, said tubular members being connected to theelongated duct opening at their upper ends for conducting pressurizedfluid downwardly therefrom to issue from the lower ends of the tubularmembers to build up and maintain a supporting fluid cushion under themachine, and a plurality of folded webs of a flexible imperviousmaterial extending downwardly between adjacent tubular members andconnected along their longitudinal edges to adjacent tubular members,said tubular components being substantially funnel shaped with thelarger opening at the top and tapering downwardly to form a jet orificeat the lower end of each tubular component, said jet orifice beinginwardly inclined toward the machine.

7. Apparatus as set forth in claim 6 wherein said folded webs aresubstantially of a U shape in cross-section.

8. Apparatus as set forth in claim 7 wherein said webs are connected tosaid tubular members along longitudinal lines which are disposedinwardly of the center lines of said flexible tubular members toward theunderside of the machine such that when viewed in cross-section agreater portion of the perimeter of each tubular member is disposedoutwardly of the machine between said longitudinal lines than isdisposed inwardly of the machine between said lines, whereby the tubularmembers will stand proud as longitudinal ribs on the outer surface ofthe skirting system when the folded webs are extended laterally.

9. Apparatus as set forth in claim 8 wherein said tubular members eachcomprise two connected wall members, said wall members being connectedalong said longitudinal lines to each other and to an edge of one ofsaid folded webs, the wall member which is disposed inwardly of themachine being of less circumferential length than the wall member whichis disposed outwardly of the machine.

Fit

BENJAMIN HERSH, Primary Examiner.

A. HARRY LEVY, Examiner.

R. M. WOHLFARTH, M. s. SALES Assistant Examiners.

1. A GROUND EFFECT VEHICLE PROVIDED WITH A FLUTED OR PLEATED FLEXIBLEJET SKIRTING SYSTEM THROUGH WHICH AIR UNDER PRESSURE IS DISCHARGEDDOWNWARDLY TO BUILD UP AND MAINTAIN THE AIR PRESSURE OF THE GROUNDEFFECT AIR CUSHION, THE SYSTEM FORMING ALSO A FLEXIBLE BARRIER TO THEDISSIPATION OF PRESSURIZED AIR CONSTITUTING THE GROUND EFFECT AIRCUSHION ASSOCIATED WITH THE BARRIER, AND COMPRISING AN ASSEMBLY OFFLEXIBLE TUBULAR COMPONENTS FORMED OF A FLACCID IMPERVIOUS MATERIAL SOAS TO BE FLEXIBLE IN ALL LATERAL DIRECTIONS AND ARRANGED IN SIDE BY SIDERELATIONSHIP TO DEPEND DOWNWARDLY FROM THE BASE OF THE VEHICLE, SAIDTUBULAR COMPONENTS BEING OPEN AT BOTH ENDS FOR PASSING PRESSURIZED AIRDOWNWARDLY THERETHROUGH, ADJACENT PAIRS OF FLEXIBLE